Patients suffering from debilitating pulmonary arterial hypertension, or PAH, find extensive relief when treated with ambrisentan. Also known as the brand name Letairis, marketed by Gilead, ambrisentan is effectual at preventing the thickening of the blood vessels, particularly those in the heart and lungs. Ambrisentan, CAS number 177036-94-1, treats the high blood pressure in the arteries of the patient’s lungs, lowers their blood pressure and helps the heart to pump better and more efficiently.
Ambrisentan is available in oral tablets, both 5 and 10 milligrams. Typically taken orally with or without food, the initial dose for the majority of patients is 5 milligrams once a day. The dose may be increased if needed on a case by case basis to 10 milligrams once a day. Side effects may include vomiting, headache, constipation, stomach pain, sinus pain and sore throat. Due to the risk of serious birth defects, Letairis is currently only offered to patients through a program called LEAP, or Letairis Education and Access Program, in the United States. This is not the standard worldwide. As Letairis approaches the end of it’s patent December 30, 2014, researchers are seeking to develop generic formulations of this unique product to provide greater options for patients.
One of the distinct benefits of ambrisentan is how effective it is at improving the ability of patients to exercise, and also preventing the PAH condition from getting worse. The patient population suffering from untreated pulmonary arterial hypertension experiences symptoms such as shortness of breath, especially when exercising, exhaustion, fainting, dizziness and swelling of the extremities, specifically the legs and arms. Ambrisentan aids patients by blocking the effects of a substance called endothelin, a small peptide hormone which is made by the body in greater then normal amounts in patients with PAH. This excess endothelin causes the blood vessels to constrict and leads to an overgrowth of the muscle in the walls of the blood vessels in the lungs. Efficacious at blocking the action of endothelin, ambrisentan is a boost for the health and activity of people in this patient group. There have been gratuitous amounts of studies completed regarding ambrisentan, primarily sponsored by Gilead, which indicated significant benefits to patients who received the drug. These aforementioned studies were mainly short term, and randomized, however there were also several long term open label trials as well. Data recorded from both short and long term trials demonstrated clearly that ambrisentan improves exercise capacity and delays clinical worsening in PAH patients. Other benefits to the administration of ambrisentan include a low incidence of liver toxicity, a lowered incidence of interactions with other drugs, including anticoagulants, and a potent bioavailability which allows even low doses for a therapeutic effect. LGM Pharma is a provider of the API ambrisentan for research and development purposes.
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